In a machining device such as a lathe, when an elongated workpiece is machined, the middle portion of the workpiece, as well as both end portions thereof, is supported to prevent the middle portion from being deflected by its own weight.
As such a machining device, conventionally, for example, a device disclosed in Japanese Unexamined Patent Application Publication No. 2004-261935 has been known. In this machining device, one end portion of a workpiece is supported by a spindle of a fixed headstock while the other end portion thereof is supported by a spindle of a sliding headstock, and the middle portion thereof is supported by a center rest.